"""
MCP gateway router — mounts SSE transport at /mcp/sse and /mcp/messages.

All requests that invoke agents are forced to local (Ollama) mode inside
server.py before any agent reasoning begins. The MCP client (e.g. Claude Code
CLI) only ever receives tool *results*, not any LLM completions.
"""
from __future__ import annotations

import logging

from mcp.server.models import InitializationOptions
from mcp.server.lowlevel import NotificationOptions
from starlette.requests import Request
from starlette.responses import Response
from starlette.routing import Route

from ..mcp.server import create_mcp_server, build_sse_transport

logger = logging.getLogger(__name__)

# Singletons created once at module import time
_mcp_server = create_mcp_server()
_sse_transport = build_sse_transport()

_INIT_OPTIONS = InitializationOptions(
    server_name='activeblue-ai',
    server_version='0.1.0',
    capabilities=_mcp_server.get_capabilities(
        notification_options=NotificationOptions(),
        experimental_capabilities={},
    ),
)


async def handle_sse(request: Request) -> Response:
    """SSE endpoint — client connects here to establish a session."""
    logger.debug('MCP SSE connection from %s', request.client)
    async with _sse_transport.connect_sse(
        request.scope, request.receive, request._send
    ) as streams:
        await _mcp_server.run(streams[0], streams[1], _INIT_OPTIONS)
    return Response()


async def handle_post_message(request: Request) -> Response:
    """POST endpoint — client sends JSON-RPC tool call messages here."""
    await _sse_transport.handle_post_message(
        request.scope, request.receive, request._send
    )
    return Response()


# Starlette routes to be added to the FastAPI app
mcp_routes = [
    Route('/mcp/sse', endpoint=handle_sse, methods=['GET']),
    Route('/mcp/messages', endpoint=handle_post_message, methods=['POST']),
]